The present disclosure relates to downhole measurements and, more particularly, to measuring the tension on a conveyance line with a downhole device.
After drilling and completing a wellbore that traverses a hydrocarbon-bearing formation, a tool string may be deployed down the wellbore to perform further operations on the wellbore. The tool string may be deployed using any number of conventional deployment methods, such as wireline or slickline deployment. The tool string may include a number of downhole tools and may additionally include equipment for monitoring conditions downhole. One example of a post-completion downhole tool that may be used is a perforating assembly, used in preparation for fracking and/or production operations. Upon conveyance of the tool downhole, one or more perforating guns associated with the perforating assembly are triggered to perforate the walls of the casing and wellbore and allow extraction of hydrocarbons from surrounding subterranean formations.
A telemetry cartridge is typically also included in tool strings and configured to communicate downhole information to the well operator at the surface. A casing collar locator (CCL) may optionally be attached to the telemetry cartridge. The CCL proves useful by passively detecting casing collars as the tool string is deployed or retrieved from the wellbore, thus resulting in providing the well operator with real-time depth information for the tool string. However, the CCL may not have sufficient signal to work in all ranges of casing sizes. The telemetry cartridge may also include tension measurement sensors to measure tension on the conveyance line. This tension information is important to the well operator as the conveyance line is typically connected to the downhole tool via a socket designed to separate the conveyance from the tool string upon experiencing a predetermined tensile load. Thus, the tension information may help the well operator prevent an unintentional disconnect of the tool string from the conveyance.
Unfortunately, operation of certain downhole tools, such as perforating guns, create violent disturbances which can damage the telemetry equipment and require repair or replacement of such equipment. Due to the potential for damaging telemetry equipment while using perforating equipment downhole, the telemetry cartridge and its associated sensors are often omitted from the tool string, thus depriving the well operator of valuable downhole information.